The investigators propose to generate a high density map of the mouse genome based on single nucleotide polymorphisms (SNPs). The SNPs they identify will be made readily available through dbSNP. They will also develop and market reagents to score these SNPs. This Phase I application is focused on producing a 1 cM, SNP-based map of chromosome 11 by re-sequencing STSs (sequence tagged sites) in 10 widely used inbred mouse strains. In preparation for a Phase II application, they will compare different strategies of obtaining suitable initial sequence data in genomic regions where it is lacking. The investigators will also explore the use of molecular beacons as an inexpensive, high-throughput assay for genotyping with SNPs. Successful completion of the Phase I aims will allow them to accurately determine the quickest and most cost effective strategy for completing the genome-wide SNP map and producing marketable assays for detection of the SNPs. PROPOSED COMMERCIAL APPLICATION: 1. NHGRI requires that we post the SNP data at dbSNP (NCBI). 2. Develop and maket reagents to score these SNPs.